I play regularly against an allies player who is ARtillery and indirect fire weapon heavy. We regularly run into the debate on wether artillery (ignores line of sight) also ignores cover because, say a ruined wall which provides hard cover can have a line of sight drawn from the observer to the target without intersecting another piece of terrain, but the wall is blocking line of sight (and providing full cover) from the direction of the artillery weapon. So far the league "overseer" has ruled that it does not ignore cover, but for future play outside of the league I would like to know if that's a house rule that's been established, or the way the game mechanic is actually supposed to be played.

Bi0mech81 said:

Artillery does not require line-of-sight from the firing model, but instead may use a model with Artillery Strike. You do draw line-of-sight from the model with Artillery Strike and unless the weapon used has Burst, it does not ignore cover.

Since line of sight will be drawn by the unit with the radioman, you will use that line of sight to determine what the cover is that the unit will get. In this case, the cover represents visibility - if it's hard for the radioman unit to see the unit, that makes it harder to give precise co-ordinates for the attack.